Energy industry figures said the government’s slow process risked the UK losing out as global companies choose other countries in which to invest.

“Clearly the more you delay decision-making, the more timetables slip, then the more uncomfortable people feel about making their own business decisions,” Louise Kingham, the chief executive of the Energy Institute, told the Guardian.

“There is a danger that investment capital can go somewhere else.”

Tidal Lagoon Power last week wrote to the business secretary, Greg Clark, and the first minister of Wales, Carwyn Jones, arguing that the lagoon would contribute more than £2bn to the UK economy over its lifetime.

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The firm said the project could be built for a guaranteed price of power, known as a contract for difference (CfD), at the same level as that awarded for the Hinkley Point C nuclear power station in Somerset.

“Subject to a mutually agreed arrangement with the Welsh government, which is under discussion, the pathfinder tidal range project in the UK requires the same level of CfD support as new nuclear power station Hinkley Point C,” a company presentation said.

The government, by contrast, has said it believes the lagoon would be twice as expensive as Hinkley.